Vacuum mandrel



E. A. LINK VACUUM MANDREL Sept. 11, 1951 2 Sheets-Sheet 1 F iled Oct. 21, 1947 INVENTOR. J I /2.4

A7 A7 V747 Patented Sept. 11, 1951 VACUUM MANDREL Edwin A. Link, Milwaukee, Wis., assignor to Mc- Graw Electric Company, a corporation of Delaware Application October 21, 1947, Serial No. 781,073

. 1 Claim.

This invention relates to vacuum mandrelsi In making capacitors, long ribbons of metal foil and dielectric are Wound into a cylindrical form and are then usually flattened. These ribbons are delicate and easily injured and it has been found difiicult to start the winding and hold the ribbons to the mandrel and to remove the wound assembly without damage to the ribbons- This invention is designed to overcome the above noted difficulties and objects of this invention are to provide a novel form of vacuum mandrel which will hold the ribbons to the mandrel and insure compact and uniform winding and which will provide means for readily detaching and freeing the wound assembly from the mandrel so that it may be freely slipped from the mandrel without any injury to the ribbons although the mandrel is not tapered but is a true cylinder throughout.

Embodiments of the invention are shown in the accompanying drawings, in which:

Figure 1 is a longitudinal sectional view showing one form of mandrel,v such view being partly broken away.

Figure 2 is a section on the line 2-2 of Figure 1.

Figure 3 is a front end view of the structure shown in Figure 1.

Figure 4. is a longitudinal sectional view showing a further form of mandrel, such view being partly broken away.

Figure is a side view of the structure shown in Figure 4 on a reduced scale and showing the manner in which the mandrel is connected to the three-way valve.

Referring to Figures 1, 2, and 3 of the drawings, it will be seen that the apparatus comprises a support or body portion l in the form of a plate to which is rigidly attached an axle or rod 2. This rod projects outwardly from the support I and the rotary mandrel 3 is mounted thereon preferably supported by means of ball bearings 4 and 5 adjacent its inner and outer ends. An end plate 6 is carried by the mandrel and is provided with a circular groove in which felt or other packing I is positioned. This felt may be cemented to the end plate 6 if desired.

Means are provided for rotating the mandrel and may comprise a worm wheel 8 and a driving worm 9 located within a casing Ill provided with front plate II. This plate is provided with a circular groove within which a suitable packing, such as felt, is positioned and cemented in place. The packing I2 is arranged to bear against the worm wheel 8 and together with the packing 1 substantially cuts ofi the opposite ends of the mandrel from communication with the outside air. The mandrel it will be noted is rigidly attached to the worm wheel 8 and is hollow and is provided with a plurality of apertures l3 extending radially inwardly to its hollow interior.

The rod or stationary shaft 2 is provided with a passageway l4 which communicates with the hollow interior of the mandrel 3. The reduced end of the shaft or support 2 is threaded and receives a fitting l5 by means of which a pipe [6 is connected thereto. The pipe 16 is connected to a three-way valve indicated generally by the reference character IT. This three-way valve is arranged to connect the pipe l6 and consequently the hollow interior of the mandrel with a source of vacuum as indicated by the vacuum pipe l8 or with a source of compressed air as indicated by the compressed air pipe [9.

In using the apparatus the three-way valve is turned to the position shown to connect the interior of the mandrel with the vacuum source and thus produce suction at all of the openings l3 in the mandrel. The outermost sheet of dielectric ribbon is brought into contact with the mandrel and the mandrel is rotated. This sheet is held by suction to the mandrel and is wound thereon and the other sheets of dielectric ribbon and foil ribbon are led into the space between the first sheet and its partially wound portion. The winding is continued until the requisite number. of layers has been formed. A suitable counting means not shown is usually provided. It is to be noted that the sheets are held tightly to the mandrel and there can be no slipping whatsoever. In addition to this, these sheets are entirely undamaged during this winding process.

When a sufiicient number of layers has been formed the mandrel is stopped, the sheets are cut across, and the three-way valve I! is turned to the compressed air source and air under pressure is thereby forced between the mandrel and the innermost sheet, thus producing a minute film of air between the wound assembly and the mandrel. This allows the wound assembly to be readily slipped ofi the mandrel.

In the form of th invention shown in Figures 4 and 5 the support or plate I is provided with a bearing supporting casing 20 on its rear side and revolubly carries the shaft 2|, preferably ball bearings 22 and 23 being provided at spaced drel and consequently with the apertures 25. The m ripheral surface to its hollow interior, sealing shaft 2| is connected by means of a rotary air coupling 2'! with a pipe 28. This pipe is connected with the three-way valve I! by means of a flexible hose or tubing 2% so that any jarring,

or slight motion of the pipe Z8 will not be com- 15 municated to the three-way valve IT.

This form of the inventionds-used:inidentically the same manner as that previously described. The mandrel is rotated in any suitable manner as by means of the worm wheel 30 driven 20 by theworm 3 I.

It will be seen that novel forms of vacuum mandrels have been provided: by this invention which are particularly'useful in the winding of th delicate dielectric and foil ribbons of ca- 25 so Although this invention has beendescribed in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the invention maybe variously embodied 'and' is to beinterpreted as claimed.

I claim:

A vacuum mandrel construction comprising a support, a stationary rigid shaft projecting outwardly from and carried by said support and having a passageway from its inner end and opening through said shaft at a point in front of said support, a mandrel revolubly carried by said 'sha'ftgarfdha'ving ahbll'dw'inteiio'r'commumeating with" said passageway and having a plurality of openings extending from its outer pemeansfor opposite ends of said mandrel, a source of vacuum, a sourceof compressed air, and means for selectively-fconnecting said passageway with saidsource o'f'vjacfuum and said source of compressed air.

" Iv EDWIN A. LINK.

REFERENCES CITED The followingrefererfces are of record in the file of this-patent? UNiTED STATES. PATENTS Number Name Date 1,271,132 Chesney.- H July 2, 1918 1,706,826 Steiger' Mar; 26, 1929 1,926,536 Herrmann .Sept. 12, 1933 1,963,381 Purdys June 19, 1934 2,415,075 Abbott Feb. 4,.1947

' FOREIGN PATENTS Number 7 Country Date 3,933 GreatBritain Dec. 4,1873 7 8,217 Sweden.- Apr. 22, 1 897 635,353 Germany- June 18,-1937 

